Cooling device

ABSTRACT

The present invention relates to a cooling structure for motor of fan, which includes a housing, an impeller and a circuit board. The housing has an air flow channel and a base; the base is located on one side of the air flow channel to support the circuit board, and the impeller is movably integrated on the base; the circuit board is bonded with a highly heat-conductive metal on at least one side thereof so as to provide good heat dissipation and heat transfer performance; at least one portion of the circuit board is extended beyond the hub of the impeller such that the extended portion is located at a downwind place of the blades of the impeller to facilitate fast heat dissipation.

FIELD OF THE INVENTION

The present invention relates to a cooling structure for motor of fan, and more particularly to a cooling fan that achieves the object of temperature rise for its heat-generating electronic components without changing the original mechanism design, to prolong the operation lifespan of fan.

BACKGROUND OF THE INVENTION

As shown in FIG. 1 and FIG. 2, a conventional cooling fan structure includes a housing 1, an impeller 2 and a circuit board 3.

The housing 1 has an air flow channel 10, an air inlet, an air outlet, a base 13 and a stator set 14, in which the air flow channel 10 accommodates the impeller 2 such that air flow is inputted from the air inlet 11 and outputted from the air outlet 12, the base is located beside the air inlet 12 for carrying the circuit board 3, and the stator set 14 and is integrated with the impeller 2.

The impeller 2 has a hub 21, a spindle 22, several bladed and an annular magnet 24, in which the spindle 22 is located centrally within the hub 21 and is movably bundled on the base 13, and the blades are circularly disposed around the periphery of the hub 21.

A sensing component 31 and at least a heat-generating electronic component 32 are disposed on the circuit board 3 for controlling alternate excitation of the stator set 14 to impel and rotate the impeller 2. Air flow is further driven by the blades 23 to flow from the air inlet 11 to the air outlet 12.

Whereas, the gate current direction of the heat-generating electronic component 32 is controlled with a metallic/non-metallic doping material with semi-conductivity. As a result, while the heat-generating electronic component is operated, its material certainly consumes partial electrical energy and converts that into thermal energy. However, structurally, the heat-generating electronic component 32 is located within the range covered by the base 13 and the hub 21. Accordingly, the heat-generating electronic component 32 lacks of an adequate cooling mechanism, easily impacts on its operational stability due to an excessively high temperature and even deteriorates the efficacy and lifespan of the cooling fan.

Therefore, the inventor of the present invention has invented a cooling fan as shown in FIG. 3 and FIG. 4 to improve the shortcoming of the conventional structure. Such cooling fan has a protrusion 30 extended from the circuit board 3 and beyond the hub 21 of the impeller 2. The heat-generating electronic component 32 is disposed on the protrusion 30 so that one part or the entire heat-generating electronic component 32 is located at a downwind place of the blades 23 of the impeller 21, thereby dissipating the heat of the heat-generating electronic component 32 by virtue of air flow guided by the blades 23.

The cooling fan previously developed by the present invention can surely reduce the temperature rise of the heat-generating electronic component 32 and prevent from affecting the overall performance and lifespan of the cooling fan as a result of high temperature. However, such solution also gives rise to the issues of the conflict between the blades 23 and the heat-generating electronic component 32 accruing electrostatic interference at the same time.

In original mechanism design of the cooling fan, a minimum safety distance H is maintained between the bottom edge of the hub 21 of the impeller 2 and the circuit board 3. However, after the protrusion 3 and the heat-generating electronic component 32 are extended beyond the hub 21, the distance h between the bottom edge of the hub 21 of the impeller 2 and the heat-generating electronic component 32 will be diminished and thus will result in a conflict between the impeller 2 and the heat-generating electronic component 32 because it is less than the minimum safety distance H. If intending to prevent the conflict, the original mechanism design of the cooling fan must be altered. Furthermore, when one part or the entire heat-generating electronic component 32 is located at a downwind place of the blades 23, it is equivalent to a situation directly exposed to an air flow field guided by the blades 23, making electrostatic charge generated by air collision in the flow field interfere with the normal operation of the heat-generating electronic component 32 or even cause malfunction thereof.

SUMMARY OF THE INVENTION

In view of the foregoing concern, the present invention thus provides a cooling structure for motor of fan, whose main object targets at achieving the function of lowering the temperature rise of a heat-generating electronic component under the premise of no change of the original mechanism design. The cooling structure has a highly heat-conductive metal integrated with at least one side of a circuit board to enhance the heat dissipation area and heat transfer performance of the circuit board, and at least one part of the circuit board is protruded beyond a hub of an impeller so as to position the protrusion at a downwind place of blades of the impeller to facilitate fast heat dissipation. Consequently, the present invention can carry out heat dissipation of the entire circuit board and the heat-generating electronic component by the heat transfer function of the highly heat-conductive metal to similarly attain a good cooling mechanism without altering the original mechanism design.

A second object of the present invention is to prevent the heat-generating electronic component from being interfered by electrostatic charge in the air flow field. The present invention can carry out heat dissipation of the entire circuit board and the heat-generating electronic component such that the heat-generating electronic component on the circuit won't be necessarily exposed in the air flow field so as to ensure that its normal operation function won't be interfered due to electrostatic interference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view showing a conventional structure;

FIG. 2 is a cross-sectional view showing the conventional structure;

FIG. 3 is a plane view showing a prior cooling fan developed by the inventor of the present invention;

FIG. 4 is a cross-sectional view showing the prior cooling fan developed by the inventor of the present invention;

FIG. 5 is a 3D exploded view showing a first preferred embodiment of the present invention;

FIG. 6 is a plane view showing the first preferred embodiment of the present invention;

FIG. 7 is a cross-sectional view showing the first preferred embodiment of the present invention;

FIG. 8 is a plane view showing a second preferred embodiment of the present invention; and

FIG. 9 is a cross-sectional view showing the second preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

To make the object, characteristic and performance of the present invention more self-explanatory, two preferred embodiments of the present invention are provided as follows together with the illustration of the figures.

As shown in FIG. 5, a first preferred embodiment of the present invention includes a housing 1, an impeller 2 and a circuit board 3.

Together with the reference to FIG. 6 and FIG. 7, the housing has an air flow channel 10, an air inlet 11, an air outlet 12, a base 13 and a stator set 14. The air flow channel 10 can accommodate an impeller 2, the air inlet 11 and the air outlet are located on both sides of the air flow channel 10 such that air flow is inputted to the air inlet 11 and outputted from the air outlet 12, the base 13 is selectively disposed beside the air outlet 12 or the air inlet 11 depending on the requirement of actual heat-dissipation occasion and has a plurality of ribs 130, a shaft tube 131 and at least a cable gap 133, in which each rib 130 is connected with the inner wall of the air flow channel 10 of the base 13 and the housing 1, one rib corresponding to the cable gap 133 is equipped with a cable slot 132 for a power cord of the circuit board 3 allowing the power cord of the circuit board 3 to reach out, the shaft tube 131 can be integrally formed or assembled on the center of the base 13, the stator set and the circuit board 3 are all fixedly disposed on the base 13 to generate alternate excitation.

The impeller 2 has a hub 21, a spindle 22, several blades 23 and an annular magnet 24, in which the spindle 22 is located centrally within the hub 21 and is movably coupled in the shaft tube 131, the blades 23 are circularly disposed around the periphery of the hub 21, and the annular magnet 24 is disposed on the inner wall of the hub 21 to sense the alternate excitation of the stator set 14 and impel and rotate the impeller 2 so as to further drive air to flow in the air inlet 11 and flow out the air outlet 12.

The circuit board 3 can be selected from a flexible printed circuit board or a regular printed circuit board, whose one side is installed with a highly heat-conductive metal, e.g. copper, aluminum, zinc, and so forth, to increase the cooling area and heat transfer performance of the circuit board 3. The circuit board 3 has at least a sensing component 31 and at least a heat-generating electronic component 32 thereon and has at least a protrusion 30 extended beyond the hub 21 of the impeller 2 and located at a downwind place of the blades, such that air flow guided by the blades simultaneously dissipate heat generated by the entire circuit board 3, the sensing component 31 and the heat-generating component 32.

Moreover, the protrusion of the circuit board 3 is preferably designed in the proximity of the cable gap 133, and after the protrusion 30 is extended outwards in a radial direction, it is close to or exactly positioned above the rib 130 equipped with the cable slot 132. On the one hand, air flow driven by the blades can still dissipate heat generated by the circuit board 3 to prevent from impacting on the operational stability and the rated output power of the heat-generating electronic component 32 and further prolong the operation lifespan of the fan; on the other hand, when the protrusion 30 is located above the rib 130 equipped with the cable slot 132, it will facilitate to relatively alleviate the turbulence and noise generated by the contact of the protrusion 30 and air flow.

When the protrusion 30 of the circuit board 3 in the present invention is extended beyond the hub 21, a default minimum safety distance H maintained between the bottom edge of the hub 21 and the circuit board is unchanged. As a result, there will be no conflict generated by the hub 21 or the blades 23, and thus it is unnecessary to modify the original mechanism design of the present invention, thereby lowering the afresh development and design cost. The heat-generating electronic component 32 of the present invention is located within a range covered by the based 13 and the hub 21. The highly heat-conductive metal combined with the circuit board 3 is employed to provide good heat dissipation and heat transfer performance. Hence, it is unnecessary for the heat-generating electronic component 32 to be exposed in air flow field, meaning that the heat-generating electronic component 32 is free from electrostatic charge that interferes with its normal operating function.

As shown in FIG. 8 and FIG. 9, which relate to the second preferred embodiment of the present invention, the shape of the circuit board 3 can be selected from one of circle, rectangle, sector, and so forth; the circle having its two sides incised forms a quasi-rectangular shape, and at least a portion of the circuit board 3 is extended beyond the hub 21 of the impeller 2 to position at least a portion thereof at a downwind place of the blades 23; for example, the diameter of the circular circuit board can be enlarged to one greater than that of the hub 21, and rectangular and sector circuit boards have at least one side or at least one corner extended beyond the hub 21; the circuit board 3 can be selected from either a flexible printed circuit board or a regular printed circuit board and at least one side thereof is bonded with a highly heat-conductive metal to increase the cooling area and the heat transfer performance of the circuit board 3.

As such, the present invention can achieve the object of lowering temperature rise of the entire circuit board 3 and the heat-generating electronic component 32 without changing the original mechanism design, and to reduce the development and design cost and prolong the operation lifespan of the fan. Meanwhile, the heat-generating electronic component 32 won't be necessarily exposed in an air flow field, thereby avoiding the resulting electrostatic charge to interfere with its normal operation performance.

In sum, from the above-mentioned characteristics those features not only have a novelty among similar products and a progressiveness but also have an industry utility.

While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. 

1. A cooling structure for motor of fan, comprising: a housing having an air inlet, an air flow channel, an air outlet and a base, wherein said air inlet and said air outlet are located on both sides of said air flow channel, and said base is disposed on one side of said air flow channel; an impeller rotationally integrated on said base and having a hub and a plurality of blades; and a circuit board disposed on said base, wherein at least one side thereof is installed with a highly heat-conductive metal, and at least one portion thereof is extended beyond said hub of said impeller, so that said extended portion is located at a downwind place to facilitate heat dissipation.
 2. The cooling structure of claim 1, wherein said circuit board is selected from one of flexible printed circuit board and regular printed circuit board.
 3. The cooling structure of claim 1, wherein said highly heat-conductive metal is chosen from one of aluminum and zinc.
 4. The cooling structure of claim 1, wherein said circuit board has a protrusion extended beyond said hub of said impeller and located at a downwind place of said blades.
 5. The cooling structure of claim 4, wherein a plurality of ribs are provided between said base and an inner wall of said air flow channel, at least a rib is equipped with a cable slot, and said protrusion is located above said rib with said cable slot.
 6. The cooling structure of claim 1, wherein said circuit board has a form selected from one of circle, rectangle and sector.
 7. The cooling structure of claim 6, wherein said circular circuit board has a diameter expandable to be greater than that of said hub.
 8. The cooling structure of claim 6, wherein said rectangular and sector circuit boards have at least one side or at least one corner extended beyond said hub. 